The present invention generally relates to data transmission systems, and more particularly to a data transmission system which automatically transmits data to a host via a communication line. For example, the data is input from a bar code reader, a keyboard and the like and is stored in a portable terminal equipment which makes the automatic transmission.
Conventionally, there is a known portable terminal equipment which has a memory for storing data input from a bar code reader, a keyboard and the like, so that the stored data can be transmitted to a host via a communication line such as a public telephone line. When transmitting the data from such a portable terminal equipment, the portable terminal equipment is coupled to the communication line before displaying an operation menu on a display screen so as to select the "transmission" menu to start the data transmission. Alternatively, a "transmission key" of the keyboard is pushed to start the data transmission.
However, the conventional portable terminal equipment suffers from the following problems.
First, the operation of the portable terminal equipment is troublesome when transmitting the stored data to the host, because it requires the selection of the menu or the manipulation of a key to start the data transmission.
Second, the operator may forget to transmit the stored data to the host because the stored data will not be transmitted unless the operator specifically instructs the data transmission by selecting the menu or manipulating the key.
Third, the portable terminal equipment is not user-friendly because the data transmission will not be started unless the user performs an operation.
Therefore, there is a demand to realize a portable terminal equipment in which the above described problems are eliminated.